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**Traffic Light Signal Colors and Their Meanings**

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**Introduction**

Traffic lights are signaling devices positioned at road intersections, pedestrian crossings, and other locations to control the flow of traffic. These devices utilize a universal color-coded system to convey different commands—namely, when to stop, when to proceed with caution, and when to go. The color of traffic lights indicating to proceed, universally recognized and adopted, is green.

**History and Development**

The concept of traffic lights dates back to the 19th century. The first known traffic signal appeared in London in 1868 near the Houses of Parliament. Designed by J.P. Knight, it was a manually operated gas-lit signal resembling railway signals of the time. However, this early attempt ended disastrously when it exploded. Despite such setbacks, the idea of controlling traffic with visual devices persisted.

The modern electric traffic light developed in the early 20th century. In 1912, Lester Wire, a policeman in Salt Lake City, Utah, theorized the first red-green electric traffic lights. But the first practical traffic lights were installed in Cleveland, Ohio, in 1914. They were based on the design by James Hoge, which allowed police and fire stations to control the signals in case of emergency. The inclusion of amber/yellow as a universal caution signal came later, with William Potts, a Detroit police officer, credited for adding this additional safety feature to the design in 1920.

**Color Coding and Its Significance**

The three colors used in traffic lights are red, yellow (amber), and green. These colors were chosen for their ability to be differentiated by those who had color blindness and for their vividness and visibility during both day and night.

- **Green**: This color is positioned at the bottom of the traffic light or on the right side in horizontal setups. Green light signals that drivers can proceed through the intersection or pass the signal point. The choice of green for go likely derives from a historical association where green has universally meant "safe" or "proceed".

- **Red**: This is typically at the top or on the left side in horizontal arrays, signaling drivers and pedestrians to stop and yield the right of way. The red signal is perhaps the most critical of the traffic light colors, as it directly concerns the safety of the intersection or crossing.

- **Yellow (Amber)**: Positioned between the green and red lights, the yellow light serves as a warning that the light is about to change from green to red. This transition period helps ensure that drivers can safely stop before the intersection if needed or finish their passage if they are too close to stop safely.

**Impact and Compliance**

Adherence to traffic light signals is crucial for maintaining smooth and safe traffic flow and reducing accidents at intersections. The standardization of these signals means that the color green, as used worldwide, helps to promote a uniform understanding and compliance, regardless of national boundaries—demonstrating the global language of traffic regulations.

**Conclusion**

Traffic lights play a fundamental role in road safety, managing the complex flows of vehicles and pedestrians at intersections. The green light, universally recognized to signal "go," has maintained a vital position in traffic regulation, ensuring clarity and uniformity in driving behaviors across the globe. As the backbone of urban traffic control, understanding and obeying these color-coded cues are essential for all road users.